Electronic device history record and product release system

ABSTRACT

A method for monitoring the manufacture of molded ophthalmic lenses is disclosed. The method monitors the occurrence of predetermined events and records such events in a device history record and a shadow table.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/247,529 which was filed on Oct. 11, 2005 now abandoned, which is acontinuation of U.S. patent application Ser. No. 11/043,311, filed Jan.26, 2005 now abandoned, which is a continuation of U.S. patentapplication Ser. No. 10/854,621, filed May 26, 2004 now abandoned, whichis a continuation of U.S. patent application Ser. No. 10/405,759, filedApr. 2, 2003 now abandoned, which in a continuation-in-part of U.S.patent application Ser. No. 10/304,399 now abandoned, filed Nov. 26,2002, which is a continuation-in-part of U.S. patent application Ser.No. 10/126,145, filed on Apr. 19, 2002 now abandoned, which is anon-provisional of U.S. Patent Application No. 60/372,619, filed Apr.12, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to manufacturing ophthalmic lenses, andmore specifically to methods and systems for recording data taken duringthe manufacturing of ophthalmic lenses such as contact lenses.

2. Background Art

Over the last several years, procedures have been developed to moldcontact lenses on a high speed automated basis, and for example, suchsystems are disclosed in U.S. Pat. Nos. 5,555,504 and 5,702,735 and U.S.patent application Ser. No. 09/305,886, filed May 5, 1999 for “Mold andMolding Machine For Making Ophthalmic Devices.” In these systems,generally, a group, or batch, of lenses is formed by sandwiching amonomer between a set of front and back mold sections. The monomer ispolymerized, thus forming the lenses, which are then removed from themold sections, further treated and packaged for consumer use.

In this process, the mold sections and the lenses are transportedthrough a number of stations or zones. For instance, the processingsystem may include filling, pre-curing, polymerizing, de-molding, andhydration stations. In order to be sure that the manufactured lenses aresuitable, various parameters must be maintained within given ranges ateach of these stations; and, accordingly, these parameters are carefullymonitored at the stations.

The number of monitored parameters can be quite large, and for example,three to eight parameters may be monitored at each station. Also, withprevious systems, all of these parameters were recorded so that acomplete history of the processing parameters was recorded and availablefor every manufactured lens. Because of the large number of lenses thatare made using these procedures and because of the large number ofmonitored parameters, this resulted in an extremely large database. Forinstance, a full print-out of the process parameters recorded while asingle batch of lenses was made might be three pages long, and over thecourse of a year, 5000 batches of lenses may be manufactured on asystem. This results in an enormous amount of data, which is expensiveto organize and to store. Moreover, government regulations require thata paper copy of each device history record be provided for each batch oflenses when the batch is shipped from the manufacturing site. Again,because of the large number of lenses made and because of the enormousamount of recorded data, finding the proper paper record for each lensand matching that paper work with the lens can be expensive, timeconsuming and also can significantly delay release of the product.

In addition, because of the significance of data recorded during thelens fabrication process, it is important to prevent the inadvertent orintentional loss or alteration of data. Heretofore, loss of data isusually solved with audit trails implemented by using the built infunctionality of the database management system. A problem with thisapproach, in the case of conventional data base management systems, isthat the audit trail includes only the type of transaction (insert,update, delete), the table affected, the time stamp of the transaction,and the user id making the transaction. This audit trail does notinclude a “before” and “after” snapshot of the data affected. Thiseliminates the ability of reports based on this data to provide acomplete picture of what happened during the fabrication process.

SUMMARY OF THE INVENTION

An object of this invention is to improve procedures for recording themanufacturing histories of molded ophthalmic lenses.

Another object of the present invention is to define a reduced set ofparameters that will provide a full history of the manufacture of moldedophthalmic lenses.

A further object of this invention is to take advantage of automateddata collection capabilities to expedite more rapid release of moldedophthalmic lenses without sacrificing quality.

Another object of this invention is to prevent the inadvertent orintentional loss of data due to user influences on production databaseworking tables.

A further object of the invention is to use the custom triggerfunctionality built into commercially available relational databasemanagement systems, to make a copy of certain data into a second, orshadow, table when certain predetermined events occur.

These and other objectives are attained with a method and system forrecording data monitored during the manufacture of molded ophthalmiclenses. This method comprises the steps of identifying a set of processparameters used in said manufacture, identifying an associated valuerange for each of the process parameters, and monitoring each of theprocess parameters during the manufacture of the lenses. If, during themanufacture of one of the ophthalmic lenses, one of the processparameters moves outside the associated value range, then that lens isrejected. However, if, during the manufacture of one of the ophthalmiclenses, all of the process parameters stay within their associatedranges, then that lens is identified as acceptable, and a device historyrecord is made for that lens. This device history record includes areference code for identifying the set of process parameters.

For example, this reference code may identify a table, kept in aseparate database, that lists all of the process parameters, and theassociated value ranges, that were monitored while the batch of lenseswas manufactured. In this way, the device history record itself does nothave to list those parameters or their associated value ranges. Thedevice history record may, it may be noted, identify one, some or all ofthese parameters, as well as their associated value ranges; but with theabove-mentioned reference code, the device history record doe not haveto list any of these parameters or their value ranges.

A database, referred to as a shadow table, may be used to protect theintegrity of data recorded during, or relating to, the manufactureprocess. More specifically, in accordance with this feature, a shadowtable is formed, and data items from device history records are copiedinto the shadow table in response to the occurrence of predefinedevents. For example, these predefined events may include wheneveranyone, or anyone outside a group of identified individuals accesses thedevice history record to perform predefined operations, such as alter ordelete, on the data in the device history record. Also, preferably,whenever any person accesses the device history record to perform agiven operation on the data in that record, a value is placed in theshadow table to identify that person, and a designation is placed in theshadow table to identify the operation performed by that person. Ashadow table may be used with device history records of the typediscussed immediately above, which contains comparatively minimalinformation, as well as with previous, or other, types of device historyrecords, which contain much more information.

Further benefits and advantages of the invention will become apparentfrom a consideration of the following detailed description, given withreference to the accompanying drawings, which specify and show preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic top view of a contact lens production lineincorporating the present invention.

FIG. 2 is a top plan view of a pallet that may be used in the productionline of FIG. 1.

FIG. 3 shows a contact lens mold assembly used in the production line ofFIG. 1.

FIG. 4 is a flow chart showing a procedure for making a device historyrecord for lenses manufactured in the system of FIG. 1.

FIG. 5 is an overview of a system that may be used to make theelectronic device histories for the lenses.

FIG. 6 illustrates the use of a shadow table in the operation of thesystem of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a lens production line system 10 implementing a datarecording procedure of the present invention. Operational details ofsystem 10 may be found in U.S. Pat. Nos. 6,071,440, 5,702,735 and5,555,504, the disclosures of which are incorporated by referenceherein. Generally, system 10 comprises various contiguously locatedstations including injection mold assembly stations 12 and 14 formanufacturing thermoplastic front and back curve contact lens moldsections, respectively. Apparatus 16 is provided for transporting up toeight front curve mold sections at a time from station 12 to a pallet20, positioned adjacent a first pallet conveyor 22, and apparatus 24 isprovided for transporting up to eight back curve mold sections at a timewithin a pallet 26 positioned adjacent a second pallet conveyor 30. Bothfirst and second pallet conveyors 22 and 30 may be partially enclosed ina low-oxygen enclosure.

A sequencing apparatus 32 for situating a pallet 20 containing frontcurve contact lens mold sections adjacent a pallet 26 containing acorresponding number of complementary back curve contact lens moldsections and onto a sequenced pallet conveyor 34 is also provided toenable pallets 20 and 26 to be conveyed alternately and sequentiallyinto a filling and mold assembly station 36. The filling/mold assemblystation 36 generally includes first, second and third apparatuses 40, 42and 44. First apparatus 40 is used to deposit, in a vacuum environment,a polymerizable compound (monomer mixture) for forming a contact lens inthe concave portion of each front curve lens mold section in each pallet20.

Second apparatus 42 is provided for depositing a surfactant along anannular rim portion of the front curve to facilitate the later removalof the back curve mold portion and the associated excess monomer ringfrom the front curve mold section in a mold separation apparatus locateddownstream of the filling station 36. Third apparatus 44 is provided forassembling the individual contact lens mold assemblies, which is done bypicking each back curve lens mold from pallet 26 and placing it onto acorresponding associated front curve lens mold located on carrier pallet20 in an oriented configuration. Additionally, after the back curves areremoved from the second pallet 26, a pallet recirculating ram assembly46 pushes the empty back curve pallets 26 back to the original backcurve supply conveyor 30 for receipt of a new set of back curve lensmold sections from injection mold assembly 14.

The pallets 20, now containing completed mold assemblies, exit thefilling/mold assembly station 36 and are conveyed along conveyor 50 to apre-cure chamber 52. At this chamber, the monomer solution contained ineach mold assembly is partially cured into a viscous gel-like state, andthe front and back curve lens mold sections are subjected to apredetermined pressure to further define the contact lens edges.

After exiting the precure chamber 52, the pallets containing theprecured lenses are transported along conveyor 50 to a polymerizationstation 54, where the precured lenses contained in the individual moldassemblies are fully polymerized in UV ovens to form the contact lensblank. Preferably, the sequenced pallet conveyor 50 is split into twoconveyors 50 a and 50 b to enable a longer residence time in thepolymerization chamber as the mold assemblies are polymerized. Pusherapparatus 62 is used to direct the travel of a predetermined number ofpallets containing the mold assemblies from conveyor 50 to each of thetwo conveyors 50 a and 50 b.

After the polymerizable compound in each of the mold assemblies ispolymerized to form a contact lens blank at the polymerization station54, the pallets travel through a demold buffer area 64, which providestemperature adjustment to the mold assemblies exiting the ovens. Thepallets then travel along a dual walking beam 66 to a back end of thesystem 20 that includes a mold separation apparatus 70. Here, the backcurve lens mold halves of the mold assemblies are automaticallyseparated from the front curve lens mold halves to expose thepolymerized contact lens for conveyance to a downstream hydrationstation 72.

After the demold process, pusher assembly 74 pushes a series of pallets20 onto a reciprocating transfer pallet apparatus 76 that conveys thepallets to the hydration assembly 72. At the hydration assembly, thefront curve lens mold sections, now containing polymerized contactlenses therein, are simultaneously removed from their respective palletsand placed in an appropriate hydration chamber (not shown) so that eachcontact lens may be hydrated prior to packaging. The transfer apparatussubsequently returns the empty pallets back to conveyor 78, where apusher assembly 80 transfers the empty first pallets back to conveyor22. Conveyor 22, in turn, transports the pallets back to a positionadjacent injection mold assembly 12 to receive a new batch of frontcurve lens mold sections from that assembly.

A top view of a production line pallet 20 for carrying production lensmold halves is shown in FIG. 2. Preferably, pallets 20 and 26 areinterchangeable so that they may accommodate either front curve or backcurve contact lens mold halves, and the production line pallets may beformed of any suitable material, such as aluminum or stainless steel.Each pallet 20 also contains a plurality of recesses 82 for receiving acomplementary pair of front and back curve mold halves that define theshape of the final desired lens. FIG. 3 shows one such mold assembly 84shown seated within a recess 82 of the pallet. The contact lenses areformed by placing an amount of polymerizable composition, generally onthe order of about 70 milligrams, in each front curve mold half 86seated within a pallet recess at the filling mold assembly 36. Then, theback curve mold half 90 is placed onto the polymerizable composition.

With reference again to FIG. 1, the production line tracking and qualitycontrol system includes a control subsystem 100, which may include acomputer or one or more programmable logic controller (PLC) and aplurality of sensor devices. These sensor devices generate processcondition information at particular stations of the facility 10 forreceipt by the computer or PLC, which controls the processes performedto the pallet carrying mold halves or mold assemblies at the particularstations. The respective PLC processes the received information and,when appropriate, generates control signals for corrective action,and/or generates error flags indicating that other types of interventionor correction may be needed.

In the embodiment of system 10 illustrated in FIG. 1, control subsystem100 includes at least three PLCs and associated circuitry and softwarefor providing tracking and control of the production line pallet system.A first PLC 102 a controls and tracks pallet movement from the injectionmold stations up to and including the filling/mold assembly stations. Asecond PLC 102 b provides quality control of and tracks pallet transportthrough the precure, UV polymerization, and mold separation stations. Athird PLC 102 c is provided for retaining the identification of palletsat the hydration assembly, where the contact lenses are removed from thepallets for subsequent processing. Additional PLCs may be provided forcontrolling the various aspects of hydration, post hydration, lensinspection, and packaging stations, as described in U.S. Pat. No.5,836,323 for “Automated Method and Apparatus for Hydrating Soft ContactLenses,” the disclosure of which is incorporated herein by reference.

Memory storage devices 104 a, b and c are provided for each PLC 102 a, band c, respectively, and have adequate addressing and storagecapabilities for each respective PLC to access and process data in theform of time information and process condition status information.Specifically, the process condition status information constitutesinformation indicating whether or not particular contact lens productsare acceptable—that is, whether process conditions involving aparticular pallet carrying contact lens mold halves or contact lens moldassemblies up to a particular point in time, have been performed inaccordance with prescribed limits and tolerances. This information isused to determine whether the products carried by that specific palletare acceptable. The specific pallet will be rejected by appropriatemeans provided in the system 10 if a product or products carried by thepallet are determined to be out of process specification parameters. Itmay be noted that the product specification parameters are determinedprior to producing saleable products off a manufacturing line byextensively running the individual steps of the line at various processconditions, e.g., temperature and pressures, etc. and testing theproduct of those steps to determine if the process conditions willultimately produce an acceptable product. From this testing, theacceptable operational ranges are determined.

A data acquisition system collects the individual process parametervalues gathered by each PLC for particular process operations, andinputs this information into a cell supervisor that associates theprocess parameters and conditions at the various process stations withthe specific pallets.

As mentioned above, the number of parameters monitored in the operationof facility 10 can be quite large, and for example, three to eightparameters may be monitored at each station in the facility. Also, withprevious systems, all of these parameters were recorded so that acomplete history of the processing parameters was recorded and availablefor every manufactured lens. With the present invention, instead ofrecording all of the values of all of the monitored parameters, asimpler data recording procedure is preferably employed. With referenceto FIG. 4, one feature of this simpler approach is, as represented atsteps 122 and 124, that if while a batch of lenses is being made in aparticular area of the machine, any process parameter moves outside itsassociated, acceptable range, the lenses in that group of pallets arerejected. The advantage of this process is that instead of rejecting anentire batch of lenses, only those lenses made outside the processparameters will be rejected. When lenses are rejected, system 10 couldbe modified to maintain a single reference code that would indicate whythe batch of lenses were rejected, e.g., a code that would indicate thata temperature was outside the operational ranges at injection molding,or a different code if the lens spent too much time in the uv tunnel, ora different code if the hydration water temperature was outside theappropriate range, etc. Keeping a record of why lenses are rejectedwould help to make the proper repairs; but this information would not bestored in a device history record because that is for saleable product,and instead, this information would be stored in an alternativedatabase.

A second feature of this simpler approach is used when a lens is foundacceptable, or more precisely, when a batch of lenses are foundacceptable—which is the case, it may be noted, if during the manufactureof the batch, all of the monitored processing parameters stay withintheir associated respective ranges. In this event, as represented bystep 126, a specific device history record of that batch is made andmaintained, and that device history record includes a reference code foridentifying a set of the process parameters. For example, this code mayidentify a table, kept in a separate database, that lists all of theprocess parameters and the associated value ranges that were monitoredwhile the batch of lenses were manufactured.

In this way, the device history record itself does not have to listthose parameters or their associated value ranges. The device historyrecord, however, may identify one, some, or all of these parameters, aswell as their associated value ranges; but with the above-mentionedreference code, the device history record does not have to list any ofthese parameters or their value ranges. Also, it may be noted, the factthat this record exists indicates that the monitored parameters were allwithin their associated ranges during the manufacturing process. It mayalso be noted that the device history record may include data itemsabout the lenses or their manufacture in addition to the above-mentionedreference code. For instance, the device history record may include alot number, the date of manufacture, and other information. FIG. 5 is anillustrated overview of a preferred electronic device history record andproduct release subsystem 140 for system 10. The subsystem 140 includesfour main types of components: database 142, a data collectionapplication 144, a data transfer application 146 and a user interfaceapplication 150. These components are housed either on client machinesor on network servers, depending on their function and interface needs,and FIG. 5 also illustrates the relationships of system componentsacross client machines and network servers.

The data collection application 144 is provided to work with thespecific model of manufacturing machine used on the production lines. Itcollects data on the processing and status of the product for the devicehistory record as the product moves through each stage of themanufacturing process. Preferably, each production machine is assigned adedicated copy of the data collection application, configured and housedon the client PC attached to the machine itself. This data collectionapplication 144 works in tandem with the human-machine interface 152that provides system monitoring and operational and troubleshootingcapabilities for that machine. Each data collection application 144 isaccompanied by a local database 154 used to store data temporarily, inthe event of a loss of connectivity with the network. This backupcapability prevents data loss and minimizes machine downtime. Datastored to the temporary database 154 is uploaded to the network database142 upon reconnection to the network.

The data transfer application 146, which is preferably housed on thenetwork servers, provides the system 140 an interface to externalsystems 156 such as accounting and distribution systems. Application 146preferably operates without human intervention, driven by suitableprocess-defined algorithms transferring transactional data stored withinthe database 142 to the desired external systems.

The user interface application 150 is used to enforce the workflowestablished by management for the release of lenses from Manufacturingto Distribution, by ensuring that the data meets quality criteria. Forexample, sterilizer run records for a batch must be reviewed prior tothe release of the product of Distribution. Until all sterilizer runrecords for the batch have been reviewed to confirm to an acceptablestatus, the batch cannot be released. These workflow managementcapabilities minimize the dependency upon physical records that existedin the previous, manual process. As physical records can betime-consuming and prone to human error, automating the process improvesthe accessibility, maintainability and accuracy of live data generatedin the course of the manufacturing process. Features within theseapplications 150 interface with external data systems that record datafrom the inspection and testing of product, to enable the eDHR/PR systemto provide a “one-stop-shopping” visibility solution to expedite productrelease.

In accordance with another feature of system 10, a procedure is providedto preserve the integrity of data recorded during or relating to themanufacture process. In particular, this procedure may be used toprevent the inadvertent or intentional loss of data due to userinfluences on the production database working tables. Generally, andwith reference to FIG. 6, this can be done forming a shadow table, andcopying data from device history records into the shadow table inresponse to the occurrence of predefined events. For example, thesepredefined events may include whenever anyone, or anyone outside a groupof identified individuals accesses one of the device history records toperform predefined operations, such as alter or delete, on any of thedata in the device history record. The ability of users to access or toalter data in the shadow table is limited and controlled so that thisdata can be relied upon to get a complete picture of an instance of thedevice history record.

More specifically, data from a device history record can be copied intothe shadow table by using the custom trigger functionality built intocommercially available relational database management systems (DBSM),such as Oracle 8i, at the data definition language (DDL) level. Oracle8i, for example, may be deployed on a commercially available Sun E5000Enterprise server running a Solaris version 5.6 operating system.

Triggers are explicitly written by a programmer to accomplish a desiredtask upon the occurrence of some specific event in the DBMS. Forexample, a custom written, mandatory trigger may be executed every timea record is inserted, updated, or deleted on any of the tables relatedto the DHR. The trigger makes a copy of the data into the shadow tablethat has the same fields as the working table, as well as fields for thetype of transaction, user id making the transaction and a sequencenumber for the transaction. The shadow tables are view only to the userand therefore not directly modifiable by the user.

The database administrators are the only users who have passwordprotected access to the shadow tables in an update or delete capacity.Thus, the data in the shadow tables can be relied on to get a completepicture of an instance of the DHR data at any point in time. Since theDHR reports are based on the data in the shadow tables, we haveassurance that the DHR is reliable.

In the case of an insert or update against a working table, the triggerpreferably inserts a complete copy of the record being inserted orupdated into the shadow table, along with an appropriate designationsuch as, for example, an “I” for insert, or a “U” for update, the userid and a sequence number. This results in the last record (that is, thelatest in time before the insert or update) for the item in the workingtable being the same information as the matching record in the shadowtable. If a record is deleted from the working table, the data are stillavailable in the shadow table. However, the data in the working tablewill not contain the rows deleted. The shadow table will contain a copyof the record just prior to the delete, along with, for example, a “D”for delete, the user id and a sequence number. Software code for onesuitable trigger that may be used to make and manage a shadow tablefollows.

-   -   Create or replace trigger T_Item_Data_IDD_AR AFTER INSERT OR        UPDATE OR DELETE on Item_Data for each row    -   --Erwin Bulletin Fri Jul 14 10:26:47 2000    -   --trigger on Item_Data    -   declare xactno number (11);    -   prgm varchar2 (50);    -   begin        -   select SEQ_A_Item_Data NEXTVAL INTO xactno FROM DUAL;        -   select idms_get_prgm (userenv(‘SESSIONID’)) into prgm from            dual;        -   if INSERTING then            -   insert into A_Item_Data (TRN_NOM, TRN_TYPE, TRN_PRGM,                Order_Id, Packout_Seq_Number, SKU, Master_Lot_Number,                Trail_Code, Language_Code, Label_ID, Last_User_Id,                Last_Update_Date)            -   Values (xactno, ‘I’, prgm,                :new.Order_Id, :new.Packout_Seq_Number, :new.SKU,                :new.Master_Lot_Number,                “new.Trail_Code, :new.Language_Code, :new.Label_ID,                :new.Last_User_Id,                :new.Last_Update_Date);    -   elsif UPDATING then        -   insert into A_Item_Data (TRN_NOM, TRN_TYPE,            TRN_PRGM,            Order_Id, Packout_Seq_Number, SKU, Master_Lot_Number,            Trail_Code, Language_Code, Label_ID, Last_User_Id,            Last_Update Date)    -   values (xactno, ‘U’, prgm,        :new.Order_Id, :new.Packout_Seq_Number, :new.SKU,        :new.Master_Lot_Number,        :new.Trail_Code, :new.Language_Code, :new.Label_ID,        :new.Last_User_Id,        :new.Last_Update_Date);    -   elsif DELETING then        -   insert into A_Item_Data (TRN_NUM, TRN_TYPE,            TRN_PRGM,            Order_Id, Packout_Seq_Number, SKU, Master_Lot_Number,            Trail_Code, Language_Code, Label_ID, Last_User_Id,            Last_Update_Date)

A shadow table, it may be noted, may be used with device history recordsof the type discussed above in connection with FIG. 4, which containcomparatively minimal information, and with previous, or other types, ofdevice history records, which contain much more information. The use ofa shadow table, in the above-described way, has a number of significantadvantages. For instance, the shadow table readily provides the DHR dataon demand. The risk of loss or change of important data in the devicehistory record is greatly reduced in that an intentional or inadvertentinfluence on the data could occur only by the database administrators.Developers and analysts cannot get at these shadow tables directly. Alltransactions record the user id and type of transaction along with thetransaction so that there is traceability of who made what types ofchanges. Since the DHR report is based on these shadow tables, there isa very high level of confidence in the reports based on the data. Theshadow table gives a reliable, traceable repository of DHR data thatalso provides a data analysis trouble shooting tool when we haveoccasional errors in the process.

While it is apparent that the invention herein disclosed is wellcalculated to fulfill the objects stated above, it will be appreciatedthat numerous modifications and embodiments may be devised by thoseskilled in the art, and it is intended that the appended claims coverall such modifications and embodiments as fall within the true spiritand scope of the present invention.

1. A method of recording data monitored during the manufacture of moldedophthalmic lenses, the method comprising the steps of: identifying a setof process parameters used in said manufacture; for each of the processparameters, identifying an associated value range; monitoring each ofthe process parameters during said manufacture; if, during themanufacture of one of the ophthalmic lenses, one of said processparameters moves outside the associated range, then rejecting the one ofthe lenses; and if, during the manufacture of one of the ophthalmiclenses, all of the process parameters stay within their associatedrange, then identifying said one of the lenses as acceptable, and makinga device history record for said one of the lenses, said device historyrecord including a reference code for identifying the set of processparameters wherein the device history records include data items, andfurther comprising the steps of: forming a shadow table; copying intothe shadow table data items from the device history records in responseto the occurrence of predetermined events, wherein said predeterminedevents include whenever anyone accesses one of the device historyrecords to perform any of a group of predefined operations on the dataitems in said one of the device history records; placing in the shadowtable a reference code identifying whenever any person accesses one ofthe device history records to perform a given operation on the dataitems in said one of the device history records identifying said person,and a reference designation identifying the given operation; preventinganyone not in a group of identified individuals from changing any datain the shadow table.
 2. A method according to claim 1, wherein the stepof making the device history record includes the step of making devicehistory records only for lenses identified as acceptable.
 3. A methodaccording to claim 2, wherein the step of making the device historyrecord includes the further step of including in said record the timesaid one of the lenses was manufactured.
 4. A method according to claim1, wherein the step of making the device history record includes thestep of making the device history record for one of the lenses aftersaid one of the lenses is identified as acceptable.
 5. A methodaccording to claim 1, further comprising the step of printing eachdevice history record on a single sheet of paper.
 6. A method accordingto claim 1, wherein the ophthalmic lenses are manufactured at a definedsite, and acceptable lenses are shipped from said site, and wherein themaking step includes the steps of making the device history record foreach acceptable lens before the lens is shipped from the site.
 7. Amethod according to claim 6, wherein the making step includes the stepof, at least prior to the time lenses are shipped from the site, makingdevice history records only for lenses identified as acceptable.
 8. Amethod according to claim 1, wherein the device history record does nothave any recorded values for any of the process parameters.
 9. A methodaccording to claim 1, further comprising the step of allowing onlyindividuals of an identified group to change any data in the shadowtable.